In communities all across the U.S., travelers that went to the moon and back with the Apollo 14 mission are living out their quiet lives. The whereabouts of more than 50 are known. Many, now aging, reside in prime retirement locales: Florida, Arizona and California. A few are in the Washington, D.C., area. Hundreds more are out there—or at least, they were. And Dave Williams of NASA’s Goddard Space Flight Center in Greenbelt, Md., wants to find them before it’s too late.

The voyagers in question are not astronauts. They’re “moon trees”—redwood, loblolly pine, sycamore, Douglas fir, and sweetgum trees sprouted from seeds that astronaut Stuart Roosa took to the moon and back 40 years ago.

“Hundreds of moon trees were distributed as seedlings,” says Williams, “but we don’t have systematic records showing where they all went.”